System of laying subterranean lines of electric wires



(No Model.)

H. B. COBB.

SYSTEM OF LAYING SUBTERRANEAN LINES 0P ELECTRIC WIRES.

Patented Nov. 13, 1883.

N. PETERS. Pholohlhugmphcn Wmlnngwn, n. c.

UNITED STATES PATENT OFFICE.

HENRY l3. COBB, OF YVILMINGTON, DELAVARE.

SYSTEM OF LAYING SUBTERRANEAN LINES OF ELECTRIC WIRES.

SPECIFICATION forming part of Letters Patent No. 288,310, dated November 13, 1883.

Application filed September 5, 1883. (No model.)

To all whom it may concern.-

Be it known that I, HENRY B. Conn, a citizen of the United States, residing at lVilmington, in the county of New Castle and State of Delaware, have invented a new and useful Improvement in Systems of Laying Subterranean Lines of Electric \Vires; and I hereby declare the following to be a full, clear, and exact description of the same.

My invention is in the nature of an improvement upon one feature of the construction de lined in my pending application for a patent, Serial No. 96,812, filed in the United States Patent Office June 1, 1883. The object of I5 the construction there defined is, while obviating interference from the inductive current by the known method of inelosing insulated wires within-comluctors inclosed in turn in groups within a metal conduit, to afiord improved facilities for laying as well as for removal, and for access to any of the parts. To the above end my said former application describes generally, and omitting details of construction, a metal conduit inclosing a group of metallic tubes in electrical contact with it, through each of which is inserted an insulating-tube, preferably ofhard rubber, through which last the wire is drawn.

The object of my present invention is to dis 3o pense with the metallic tubes which inclose current as results from the construction defined in my said former application; and my invention consists, first, in providing the insulating tubes through which the separate wires are passed with a close and permanent 4o coating or covering of metal; and,furthern1ore,

in certain details of construction and combinations of parts, all as hereinafter more fully set forth.

In the drawings, Figure l is a perspective view of the insulating-tube coated with metal and inclosing the wire; Fig. 2, a longitudinal section showing a manner of connecting the tubes at the man-hole and elsewhere; Fig. 3, a longitudinal section showing the tubes as connected in lengths between the manholes, and

Fig. 4. an end view of a conduit inclosing a group of the tubes and wires.

A is the tube, of insulating 1naterialsuch as hard rubber, for example-and B is a close and permanent coating or covering of metal, preferably copper, formed thereon in any convenient manner, but preferably with the aid of a battery and an acid bath.

To prepare the non-conducting tubes to receive the metal plate when the latter method is employed, any of the modes well known to those skilled in the art of metal-plating may be adopted. A good one is the following: Two solutions are formed, the first consisting of about three parts of nitrate of silver dissolved in one hundred parts of pure water, or else of a saturated solution of the nitrate with alcohol, being about two and one-fourth parts to one hundred parts, made by placing an excess of the nitrate in hot alcohol until the solution is saturated, and the second consisting of a strong solution of phosphorous bisulphide of carbon. The rubber tube is dipped into the first solution and dried, and then immersed for a few hours in the second solution within a perfectlyclosed box, after which it is plated in the usual way, using for the electrolyte a sulphateofcopper solution saturated. Instead of using a phosphorous solution, the same effect can be produced with sulphureted hydrogen gas in a close box, though the former is to be preferred.

Another way to prepare the tubes to receive the metal plate is to coat them by means of a brush with black-lead, or with a mixture of equal parts of black-lead and white bronze.

The hollow interior of the tube should have a suificient diameter to permit the ready passage through it of the wire 0. W here the wires are j oined at the man-holes or elsewhere, the ends of the tubes on opposite sides of the knot may be connected by means of a sleeve, D, of the same material as the tube, and similarly coated with metal; or a simple sleeve of soft rubber may be employed without a coating. The tubes are ordinarily made in short lengths, so that they may be handled conveniently within the man -hole, and are connected together by a slip-joint, b, as shown in Fig. 3, and pushed through the conduit F. The tubes are usually passed over the wires after the latter have been strung through the conduit.

\Vhat I claim as new, and desire to secure by Letters Patent, is

wires passed through the tubes, and a metal conduit inclosing the tubes, and in electrical 10 contact with their metal coverings, substantially as described.

" HENRY B. COBB.

In presence of D. H. FLETCHER, EDWARD 1VICCAFFREY. 

